Search Results (7,273)

As unmanned aerial vehicles (UAVs) are increasingly utilized in urban inspection and emergency rescue missions, path planning under strong wind conditions persists as a critical challenge. Traditional algorithms frequently exhibit deficiencies in environmental adaptability or encounter difficulties in balancing exploration and exploitation. This paper presents a dynamic-proportion Bat–Cuckoo Search (BA-CS) Hybrid Algorithm enhanced with wind field perception to tackle the challenges of UAV path planning in urban environments with strong winds, specifically addressing the issues of insufficient environmental adaptation and the exploration–exploitation imbalance. The algorithm integrates a dual-feedback mechanism that dynamically modifies the ratio of the BA/CS subpopulations in accordance with real-time iteration progress and population diversity. By incorporating wind field perception into population initialization, interpopulation information exchange, and wind resistance perturbation strategies, it attains efficient path optimization under multiple constraints. Experimental results under strong winds with speeds ranging from 10.8 to 13.8 m/s indicate that the proposed algorithm generates paths that are smooth, continuous, and entirely collision-free. It achieves a superior average wind resistance cost of 0.92, which is 9.8%, 17.1%, and 52.6% lower than those of the A*, RRT, and PSO algorithms, respectively. With a planning time of 3.95 s, it satisfies the path wind resistance stability requirements stipulated in the GB/T 38930-2020 standard, providing an effective solution for UAV inspection and emergency rescue operations in urban wind scenarios. Full article

Chronic kidney disease (CKD) afflicts 850 million people worldwide, with an estimate that it is the 5th highest cause of years of life lost (YLLs). Standard confirmatory procedures for disease are blood and urine analysis with ultrasound for confirmation. Neutrophil gelatinase-associated lipocalin (NGAL) has been established as a prognostic biomarker, especially for the pre-clinical stages of CKD, thus presenting itself as a dependable predictor of the progression. With the aim of designing diagnostics, fatty acids were explored as potential biorecognition elements for the selective capture of NGAL. Three fatty acids—linoleic acid, arachidonic acid, and retinoic acid—were shortlisted as plausible candidates based on their known affinity toward lipocalin family proteins. Docking followed by molecular dynamics simulations were employed to evaluate the binding affinity and stability of each complex. Among them, linoleic acid exhibited the most favorable interaction, as evidenced by the lowest binding free energy. Subsequently, fluorescence and electrochemical techniques—square-wave voltammetry, differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS)—were systematically compared for qualitative and quantitative checking of the accuracy of NGAL detection. Amongst the electrochemical techniques, differential pulse voltammetry DPV demonstrated superior analytical performance with an LOD of 0.05 ng/mL with a sensitivity of 23.2 µA/cm²/pg. To the best of our knowledge, this is the first report of a fatty acid-based biosensor platform for NGAL detection, presenting a novel approach for CKD diagnostics. The sensitivity obtained is comparable with available NGAL detection methods yet cost-effective and robust. Full article

The proliferation of biometric authentication systems in critical security applications has highlighted the urgent need for robust defense mechanisms against sophisticated adversarial attacks. This paper presents ShieldNet, an adversarially resilient Convolutional Neural Network (CNN) framework specifically designed for secure iris biometric authentication. Unlike existing approaches that apply adversarial training or gradient regularization independently, ShieldNet introduces a synergistic dual-layer defense framework featuring three key components: (1) an attack-aware adaptive weighting mechanism that dynamically balances defense priorities across multiple attack types, (2) a smoothness-regularized gradient penalty formulation that maintains differentiable gradients while encouraging locally smooth loss landscapes, and (3) a consistency loss component that enforces prediction stability between clean and adversarial inputs. Through extensive experimental validation across three diverse iris datasets, MMU1, CASIA-Iris-Africa, and UBIRIS.v2, and rigorous evaluation against strong adaptive attacks including AutoAttack, PGD-100 with random restarts, and transfer-based black-box attacks, ShieldNet demonstrated robust performance, achieving 87.3% adversarial accuracy under AutoAttack on MMU1, 85.1% on CASIA-Iris-Africa, and 82.4% on UBIRIS.v2, while maintaining competitive clean data accuracies of 94.7%, 93.9%, and 92.8%, respectively. The proposed framework outperforms existing state-of-the-art defense methods including TRADES, MART, and AWP, achieving an equal error rate (EER) as low as 2.8% and demonstrating consistent robustness across both gradient-based and gradient-free attack scenarios. Comprehensive ablation studies validate the complementary contributions of each defense component, while latent space analysis confirms that ShieldNet learns genuinely robust feature representations rather than relying on gradient obfuscation. These results establish ShieldNet as a practical and reliable solution for deployment in high-security biometric authentication environments. Full article

High-temperature proton exchange membranes (HT-PEMs) are critical components of high-temperature fuel cells, facilitating proton transport and acting as a barrier to fuel and electrons; however, their performance is hampered by persistent issues of phosphoric acid leaching and oxidative degradation. Herein, a novel HT-PEM with abundant hydrogen bond network is constructed by incorporating nanoscale polyhedral oligomeric silsequioxane functionalized with eight pendent sulfhydryl groups (POSS-SH) into poly(4,4′-diphenylether-5,5′-bibenzimidazole) (OPBI) matrix. POSS, a cage-like nanostructured hybrid molecule, features a well-defined silica core and highly designable surface organic groups, offering unique potential for enhancing membrane performance at the molecular level. Through controlled reactions between sulfhydryl groups and allyl glycidyl ether (AGE), two functional POSS crosslinkers—octa-epoxide POSS (OE-POSS) and mixed sulfhydryl-epoxy POSS (POSS-S-E)—were synthesized. These were subsequently used to fabricate crosslinked OPBI membranes (OPBI-OE-POSS and OPBI-POSS-S-E) via epoxy–amine coupling. The OPBI-POSS-S-E membranes demonstrated exceptional oxidative stability, which is attributed to the free radical scavenging ability of the retained sulfhydryl groups on the nano-sized POSS framework. After soaking in Fenton’s reagent at 80 °C for 108 h, the OPBI-POSS-S-E-20% membrane retained 79.4% of its initial weight, significantly surpassing both the OPBI-OE-POSS-20% and pristine OPBI membranes. The PA-doped OPBI-POSS-S-E-20% membrane achieved a proton conductivity of 50.8 mS cm⁻¹ at 160 °C, and the corresponding membrane electrode assembly delivered a peak power density of 724 mW cm⁻², highlighting the key role of POSS as a nano-modifier in advancing HT-PEM performance. Full article

Aging and neurodegenerative diseases are characterized by common features involving bioenergetics deficiencies, oxidative stress and alterations of calcium buffering. Mechanisms of mitochondrial-targeted drugs include the modulation of electron transport chain and oxidative phosphorylation, the binding to mitochondrial lipids, free-radical scavenging, calcium signaling, and possible effects on mitochondrial biogenesis and dynamics and on the regulation of mitophagic pathways. One of the main sites of action of mitochondria-targeted drugs is the interaction with respiratory chain components. Mitochondrial-targeted compounds such as Mito-Q, and Mito-apocynin have been developed by conjugating triphenylphosphonium (TPP⁺) lipophilic cation group with natural molecules, therefore obtaining promising drugs for reestablishing the correct functioning of the mitochondrial respiratory chain. Stabilization of cardiolipin at the inner mitochondrial membrane by elamipretide or SkQ1 and mitochondria-targeted ROS scavengers can also offer a therapeutic approach to prevent bioenergetic impairment associated with several diseases. In addition, the modulation of calcium signaling can be achieved using both MCU agonists and antagonists representing another mitochondrial target for drug therapies development. Finally, potential strategies for treating neurodegenerative diseases based on the modulation of mitochondrial biogenesis, dynamics and/or mitophagic pathways are discussed. Full article

The influence of electron beam treatment parameters (electron gun speed, electron beam current, scanning frequency, and sweep type) on the structure and properties of the surface layer of the composite material AlMg3-5SiC has been investigated. Composite specimens of AlMg₃ alloy reinforced with 5 wt.% silicon carbide particles were manufactured via the stir casting process. Experimentally, processing modes with heat input from 120 to 240 J/mm yield a modified layer thickness from 74 to 1705 µm. Heat input should not exceed 150 J/mm to ensure a smooth and defect-free surface layer. The macro- and microstructure were examined using optical microscopy. Brinell hardness was measured. Friction and wear tests were performed under dry sliding friction conditions using the “bushing on plate” scheme. This evaluated the tribological properties of the composite material in its original cast state and after modifying treatment. Due to the matrix alloy structure refinement by 5–10 times, the surface layer’s hardness increases by 11% after treatment. The modified specimens have superior tribological properties to the initial ones. Wear rate reduces by 17.5%, the average friction coefficient reduces by 32%, and the root mean squared error of the friction coefficient, which measures friction process stability, reduces by 50% at a specific load of 2.5 MPa. Therefore, the electron beam treatment process is a useful method for producing high-quality and uniform wear-resistant aluminum matrix composite surface layers. Full article

In constrained waters, multi-USV cooperative encirclement of highly maneuverable targets is strongly affected by partial observability as well as obstacle and boundary constraints, posing substantial challenges to stable cooperative control. Existing deep reinforcement learning methods often suffer from low exploration efficiency, pronounced policy oscillations, and difficulties in maintaining the desired encirclement geometry in complex environments. To address these challenges, this paper proposes an adaptive difference-based multi-agent policy gradient method (MAADPG) under the centralized training and decentralized execution (CTDE) paradigm. MAADPG deeply integrates potential-field-inspired geometric guidance with a multi-agent deterministic policy gradient framework. Specifically, a guidance module generates geometrically interpretable candidate actions for each pursuer. Moreover, a difference-driven adaptive action adoption mechanism is introduced at the behavior policy execution level, where guided actions and policy actions are locally compared and the guided action is adopted only when it yields a significantly positive return difference. This design enables MAADPG to select higher-quality interaction actions, improve exploration efficiency, and enhance policy stability. Experimental results demonstrate that MAADPG consistently achieves fast convergence, stable coordination, and reliable encirclement formation across representative pursuit–encirclement scenarios, including obstacle-free, sparsely obstructed, and densely obstructed environments, thereby validating its applicability and stability for multi-USV encirclement tasks in constrained waters. Full article

Split G-quadruplex DNAzymes offer unique opportunities for building gated biosensors with a wide range of applications. Splitting G4 DNAzymes involves separating guanine tracts in the G-quadruplex DNA sequence into two non-functional sequences that reconstitute into a functional G-quadruplex with peroxidase activity upon hybridisation of the aptamer probe region within the split system with the target molecule. Several studies have demonstrated the reassembly of split G4 DNAzymes and their applications in the detection of various analytes. This approach offers unique opportunities for modular biosensor construction, target-dependent activation, lack of requirement for labelling, amplification-free high sensitivity, and specificity over traditional G4 sensing. In this review, we explore the strategies of splitting G-quadruplex and their applications in biomedical diagnosis, environmental sensing, food safety monitoring, cell detection, and the integration of the technology with nanomaterials for enhanced stability and sensitivity. We considered the classical intermolecular split strategies that utilise binary probes and intramolecular split systems, which integrate the spacer DNA that allow for single probes as the model G4 sequence. Finally, we explore the current challenges required to develop split G-quadruplex DNAzymes into tools for routine practical applications. Full article

The accelerating global demand for sustainable energy, driven by population growth, industrialization, and environmental concerns, has intensified the search for renewable alternatives to fossil fuels. Biofuels, including bioethanol, biodiesel, biogas, and biohydrogen, offer a viable and practical pathway to reducing net carbon dioxide (CO₂) emissions. Yet, their large-scale production remains constrained by biomass recalcitrance, high pretreatment costs, and the enzyme-intensive nature of conversion processes. Recent advances in enzyme immobilization using magnetic nanoparticles (MNPs), covalent organic frameworks, metal–organic frameworks, and biochar have significantly improved enzyme stability, recyclability, and catalytic efficiency. Complementary strategies such as cross-linked enzyme aggregates, carrier-free immobilization, and site-specific attachment further reduce enzyme leaching and operational costs, particularly in lipase-mediated biodiesel synthesis. In addition to biocatalysis, nanozymes—nanomaterials exhibiting enzyme-like activity—are emerging as robust co-catalysts for biomass degradation and upgrading, although challenges in selectivity and environmental safety persist. Green synthesis approaches employing plant extracts, microbes, and agro-industrial wastes are increasingly adopted to produce eco-friendly nanomaterials and bio-derived supports aligned with circular economy principles. These functionalized materials have demonstrated promising performance in esterification, transesterification, and catalytic routes for biohydrogen generation. Technoeconomic and lifecycle assessments emphasize the need to balance catalyst complexity with environmental and economic sustainability. Multifunctional catalysts, process intensification strategies, and engineered thermostable enzymes are improving productivity. Looking forward, pilot-scale validation of green-synthesized nano- and biomaterials, coupled with appropriate regulatory frameworks, will be critical for real-world deployment. Full article

This study tackles the stabilization and delivery challenges of oxidation-prone carrot oil by engineering tailored Zein-OSA starch hybrid complexes. The influence of complex mass ratios (1:2, 1:1, 2:1) on key structural, colloidal, and functional properties was meticulously evaluated. The complexes were analyzed through spectroscopy, thermal methods, and microscopy. Derived emulsions were assessed for stability under environmental stresses (pH, salts, storage), alongside their rheological behavior and aroma retention. The 1:1 complex emerged with optimal molecular compatibility, thermal stability, and barrier properties. In emulsions, the 1:2 formulation provided the most uniform droplets and superior salt tolerance, while the 1:1 ratio yielded the best pH stability. All emulsions were shear-thinning. Microencapsulation effectively converted the emulsion into a stable, free-flowing powder. This work demonstrates a rational approach to designing robust plant-based delivery systems for protecting and improving the functionality of sensitive lipophilic ingredients in practical applications. Full article

MQ copolymers, consisting of monofunctional (M) and tetrafunctional (Q) siloxane units, are versatile materials used as additives, adhesives, and in composite materials. Functional groups, such as vinyl substituents, in M-units allow for the tailoring of properties for specific applications. This study aimed to synthesize vinyl-containing MQ copolymers (M^VinMQ) via a controlled, chlorine-free method to explore the regulation of their composition and properties. The results demonstrated precise control over the copolymer architecture, with hydroxyl content and molecular weight increasing alongside the Q-unit fraction. All obtained copolymers exhibited high thermal stability, with 5% mass loss occurring above 295 °C in air and 365 °C in argon. Fractionation data supported a molecular composite model consisting of an inorganic core and an organic shell. Polycondensation in an active medium is an effective method for the directed synthesis of structurally tunable M^VinMQ copolymers, offering a versatile platform for developing functional hybrid materials, modifiers, and cross-linking agents. Full article

The transformation of Andean grains and tubers through fermentation and bioencapsulation has emerged as a key strategy to enhance their nutritional, functional, and biotechnological value, driven by advances in proteomic and metabolomic techniques. This study aimed to systematize recent evidence on the biochemical and functional modifications induced by these processes and their potential application in the development of functional foods. The methodology integrated 67 studies analyzed using tools such as R 4.5.1 with the JupyterLab interface 4.5.2, SCImago Graphica Beta 1.0.53, and VOSviewer 1.6.20, incorporating data generated through LC-MS/MS, UHPLC-QTOF, Orbitrap platforms, transcriptomics, and combined omics approaches, considering original studies published between 2020 and 2025. The main findings indicate substantial increases in free amino acids (up to 64.8%), phenolic compounds (2.9–5.2%), and antioxidant activity (up to 45%), along with the identification of 430 polyphenols, 90 flavonoids, 14 novel oxindole acetates, and bioactive peptides with IC50 values ranging from 0.51 to 0.78 mg/mL. Bioencapsulation showed controlled release of bioactive compounds, highlighting nanocapsules of 133–165 nm with a maximum release of 9.86 mg GAE/g. In conclusion, the combination of fermentation and encapsulation enhances the stability, bioavailability, and functionality of Andean crops, supporting their industrial adoption for the development of sustainable nutraceutical foods that improve health and promote the valorization of traditional resources. Full article

During the transportation of oil and gas pipelines, the adhesion and aggregation of hydrate particles on the pipe wall are prone to cause pipeline blockage, which seriously impairs the safe and efficient transportation of energy. Taking cyclopentane hydrates as the research object, this study investigated the effects of contact time, wall wettability, and the concentration of kinetic hydrate inhibitor poly(N-vinylcaprolactam) (PVCap) on the adhesion force between hydrates and the wall of X80 pipeline steel by combining a high-precision micromechanical force measurement system with microscopic morphology observation and analysis. The results show that the adhesion force increases with prolonged contact time: it is dominated by capillary liquid bridge force in the initial contact stage with slow growth, and after exceeding the critical time, the sintering effect becomes the dominant factor, leading to a rapid rise in adhesion force that eventually tends to stabilize. Wall wettability significantly influences the adhesion force, and enhanced wettability improves the adhesion force by increasing the liquid bridge volume and the hydrate–wall contact area. PVCap concentration exerts a non-monotonic effect on adhesion force—first decreasing and then increasing. At low concentrations (0.25–1 wt%), PVCap molecules adsorb on the hydrate surface to form a physical barrier, reducing adhesion force. At high concentrations (1.5–2 wt%), excessive PVCap damages hydrate shell integrity, releasing free water to expand the liquid bridge volume and increase adhesion force. This study provides a theoretical basis for eliminating or reducing hydrate blockage in deep-sea oil and gas pipelines. Full article

Slag entrainment within the mold is a significant cause of surface defects in continuously cast slabs. As a key component for controlling molten steel flow, the structure of the submerged entry nozzle directly influences the flow field characteristics and slag entrainment behavior within the mold. This paper employs a 1:4-scale water–oil physical model combined with numerical simulation to investigate the effects of elliptical and circular submerged entry nozzles on slag entrainment behavior in a wide slab mold under different casting speeds and immersion depths. High-speed cameras were used to visualize meniscus fluctuations and oil droplet entrainment processes. An alternating control variable method was employed to quantitatively delineate a slag-free “safe zone” and a “slag entrainment zone” where oil droplets fall, determining the critical casting speed and critical immersion depth under different operating conditions. The results show that, given the nozzle immersion depth and slag viscosity, the maximum permissible casting speed range without slag entrainment can be obtained, providing a reference for industrial production parameter control. The root mean square (RMS) of surface fluctuations was introduced to characterize the activity of the meniscus flow. It was found that the RMS value decreases with increasing nozzle immersion depth and increases with increasing casting speed, showing a good correlation with the frequency of slag entrainment. Numerical simulation results show that compared with elliptical nozzles, circular nozzles form a more symmetrical flow field structure in the upper recirculation zone, with a left–right vortex center deviation of less than 5%, resulting in higher flow stability near the meniscus and thus reducing the risk of slag entrainment. Full article

Quantum technology, a critical 21st-century strategic frontier science, has been a key technological competition between China and the U.S. This study employs natural language processing (NLP) techniques and a technology analytical framework to analyze the quantum technology policies of both countries. While the U.S. emphasized free-market innovation and global technological leadership on quantum technology from 2018 to 2024, China prioritized government-led development and socioeconomic stability. Moreover, the Chinese government adopts a systematic top-down approach characterized by government planning and direct intervention. However, the U.S. fosters innovation through market mechanisms and industry-academia collaboration. U.S. policies have gradually shifted from pure technological innovation to national security considerations. On the other hand, China has moved from breakthrough research to industrial deployment and application. These policy differences reflect distinct political systems and governance models, which may also resonate with their respective cultural traditions and philosophical foundations. Our findings fill a critical gap in comparative quantum technology policy research, offering significant insights for policymakers, researchers, and international stakeholders. Full article